This invention relates to a governor for use in controlling the rate at which fuel is supplied to a fuel pump, and thus for use in controlling the operation of an engine of the compression ignition type.
A governor for use with a diesel engine of an alternator and generator set typically comprises a centrifugal weight mechanism arranged to rotate at a speed associated with engine speed and to act upon a spring biased lever, the lever being coupled to a fuel metering valve such that movement of the lever is transmitted to the valve to adjust the setting of the valve. In particular, the governor is arranged such that in the event that the load on the engine changes, a corresponding change in the fuelling of the engine is made to control the engine in such a manner that it operates at a substantially constant speed.
It is desirable to be able to adjust the governor to permit control over the change in engine speed which must occur in order for the metering valve to move between its fully open and closed positions. Such adjustment is known as xe2x80x9cdroopxe2x80x9d adjustment or control and is desirable as it allows the governor to be controlled to compensate for wear and for variations in the output of governors of identical nominal specifications. Droop control may also be used to improve the stability of the system, for example to limit engine speed oscillations following a rapid change in load.
According to the present invention there is provided a governor comprising a centrifugal weight mechanism coupled to an angularly adjustable metering valve member, and means for adjusting the axial position of the meeting valve member to permit droop control.
The invention also relates to a method of adjusting the droop of a governor comprising adjusting the axial position of a metering valve to adjust the variation in engine speed necessary to move the metering valve between two predetermined fuelling levels.